Technology Education Department
Introduction to Technical Drawing
Name: Yoon Doh
STUDY QUESTIONS FOR STEP 4
1. List three (3) uses for freehand sketches:
Sketching is a freehand drawing process that allows detailers,
designers, engineers, architects, technicians and trades persons to
record their ideas quickly on paper without the use of tools. Once
they have recorded their ideas, they can revise and refine their
sketches for presentation to their supervisors or clients. Sketching
is also helpful in preliminary planning of a drawing or layout
before using tools.
2. What does a "multiview sketch" show you about an object?
Drawing that shows the front, side, and top view.
A multiview two dimensional
(2D) sketch shows the actual shape of an object from different
directions that are 90° apart. A typical multiview sketch will
include views from the top, front and right side. The back, bottom
and left side views are optional depending on the complexity of the
objects shape.
3. List the three (3) principle views that are shown on a multiview sketch:
top, front, and right side
4. List in your own words the steps to follow in the making of a multiview sketch:
Chang Yoon Doh 2014
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Step 1 - ANALYZE THE OBJECT.
Choose the orientation. The front view is typically the view with the most detail. Study the object to determine the length, width and height.
Determine the number of views ( one, two, three or more) and the types of views (top, front, right or left side).
Select a proportional grid size (1/4" or 1/8") to represent a unit of measurement (1/4", 1/2" or 1") and the type of paper (plain white or graph) to work on.
Step 2 - LAYOUT THE VIEWS.
Begin at the lower left area of the sheet and place four dots or dashes vertically to represent the height and width of the object with about 1" of space
between the measurements. Next, return to the lower left area of the sheet and place four dots or dashes horizontally to represent the length
and width of the object with about 1" of space between the measurements.
If the views do not fit in the space available, use a larger sheet of paper (11" x 17" or 17" x 22") or reduce the proportions of the views.
Step 3 - BLOCK IN THE VIEWS.
Sketch very light construction lines horizontally and vertically at the dots or dashes to establish the outline of each view.
A 45° line in the upper right outline is helpful in projecting lines from the top view to the right side view.
Step 4 - LOCATE DETAILS.
Use very light construction lines to locate changes in the shape of the object and to show the location of holes or rounded corners.
Be sure to extend the construction lines into the adjacent view (top to front, front to side and top to side).
Step 5 - ADD DETAILS.
Use very light construction lines to create a box that represents the diameter of holes or the radius of rounded corners.
Sketch in the holes and rounded corners using 90° arcs.
Step 6 - DARKEN VISIBLE LINES.
All lines that represent visible edges of the object should be shown as solid thick lines.
Step 7 - DARKEN HIDDEN LINES.
All lines that represent interior edges or hollow portions of the object should be shown as dashed medium thick lines.
Step 8 - ADD CENTER LINES.
Use thin long and short dashed lines to locate the center of holes and arcs.
NOTE: Construction lines DO NOT need to be erased as they should be drawn very lightly.
5. What does a "pictorial sketch" show you about an object?
A pictorial three dimensional (3D) sketch shows the overall shape
of an object from one direction. There are three types of pictorial
sketches: isometric, oblique and perspective. The isometric is the
easiest to create as actual measurements are used and the shape of
arcs and circles is consistent on all surfaces. The cabinet oblique
sketch is best used for furniture or cylindrical shaped objects as a
normal front view is used. Perspective sketches provide the most
realistic view of an object but are more difficult to create as all
distances must be shortened.
6. List the three (3) principle types of pictorial sketches:
isometric, oblique and perspective
7. Why is the "isometric pictorial sketch" the most commonly used type of pictorial view?
Because it is the
easiest to create as actual measurements are used and
the shape of arcs and circles is consistent on all surfaces.
8. What overall shape should an object have to utilize an "oblique view"?
Chang Yoon Doh 2014
Wednesday, October 5, 2011 11:24:02 AM CT
34:15:9e:36:a6:aa
Cylindrical shaped objects
9. What does a "perspective sketch" show you about an object?
Perspective sketches provide the most realistic view of an object
but are more difficult to create as all distances must be shortened.
10. What does a "floor plan" and an "elevation" show you about a building?
Architects use two types of sketches, floor plans and elevations, to
show the shape of a house or building. A floor plan sketch is
similar to a top view with the roof removed and shows interior
walls, windows, doors, appliances, fixtures, built-in cabinetry and
stairways. An elevation is similar to a front view and shows the
height of the structure plus exterior materials like siding, doors,
windows, trim and roofing.
11. List in your own words the steps to follow in the making of a pictorial sketch:
Step 1 - ANALYZE THE OBJECT.
Study the object to determine the length, width and height. Determine the type of pictorial view (isometric, oblique or perspective).
Select a proportional grid size (1/4" or 1/8") to represent a unit of measurement (1/4", 1/2" or 1") and the type of paper (plain white or graph) to work on.
Step 2 - LAYOUT THE AXIS FOR AN ISOMETRIC SKETCH.
Begin at a point to the right and below the center of the sheet. At this point sketch three axis (one vertical, one to the right at a 30°
angle from horizontal and one to the left at a 30° angle from horizontal). The three axis should form a "Y" on the sheet.
Step 3 - ADD DIMENSIONS TO THE AXIS.
Estimate the height on the vertical axis and mark it with a dash. Estimate the width on the axis to the right and mark it with a dash.
Estimate the length on the axis to the left and mark it with a dash. If the measurements do not fit in the space available, use a larger
sheet of paper (11" x 17" or 17" x 22") or reduce the proportions of the views.
Step 4 - BLOCK IN THE VIEWS.
Sketch very light construction lines parallel to the axis to form a box that the object will fit in.
Step 5 - LOCATE DETAILS.
Use very light construction lines to locate changes in the shape of the object and to show the location of holes or rounded corners.
Step 6 - ADD DETAILS.
Use very light construction lines to create a diamond that represents the diameter of holes or the radius of rounded corners.
Sketch in the holes and rounded corners using one or more arcs.
Step 7 - DARKEN VISIBLE LINES.
All lines that represent visible edges of the object should be shown as solid thick lines.
Step 8 - ERASE EXCESS LINES.
Hidden lines or center lines are NOT shown.
NOTE: Construction lines DO NOT need to be erased as they should be drawn very lightly.
12. Show and label with arrows the recommended methods for sketching the following lines:
Chang Yoon Doh 2014
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Horizontal lines
Vertical lines
Angular lines
Circular lines
13. Sketch an example of a "construction" line and explain how it is used:
Construction lines are very thin, light lines and are used to layout
preliminary shapes. Construction lines should not have to be
erased.
14. Sketch an example of a "visible" line and explain how it is used:
Visible or object lines are thick, solid lines and are used to show
the outline or the visible edges of the object.
15. Sketch an example of a "hidden" line and explain how it is used:
Hidden lines are medium thick, dashed lines and are used to show
edges or surfaces on the inside of an object or behind the top, front
or side surfaces.
16. Sketch an example of a "center" line and explain how it is used:
Center lines are thin lines composed of long and short dashes and
are used to locate the center point of holes or the central axis of a
cylinder.
Chang Yoon Doh 2014
Wednesday, October 5, 2011 11:24:02 AM CT
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17. Is it necessary to erase "construction" lines? No because it is very light and it just a rough
sketch.
18. What shape does a circle become when sketched on a pictorial view?
elipse
19. Is it necessary to sketch objects in the proper "proportions"? yes
Explain: because more accurate or realistic drawing is, it is more easy to understand the drawing.
20. Make freehand sketches of the following using appropriate "proportions" in the space below :
Chang Yoon Doh 2014
1" x 2" rectangle
two 1.5" parallel lines 1/2" apart
two 3/4" perpendicular lines
1.5" diameter circle
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2" isometric ellipse
30°, 60° & 90° triangle
Chang Yoon Doh 2014
Wednesday, October 5, 2011 11:24:02 AM CT
a 45°, 45° & 90° triangle 34:15:9e:36:a6:aa